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C# Set Windows Form to front but not give it focus [duplicate]

I'm using a Form to show notifications (it appears at the bottom right of the screen), but when I show this form it steals the focus from the main Form. Is there a way to show this "notification" form without stealing focus?

Hmmm, isn't simply overriding Form.ShowWithoutActivation enough?
protected override bool ShowWithoutActivation
{
get { return true; }
}
And if you don't want the user to click this notification window either, you can override CreateParams:
protected override CreateParams CreateParams
{
get
{
CreateParams baseParams = base.CreateParams;
const int WS_EX_NOACTIVATE = 0x08000000;
const int WS_EX_TOOLWINDOW = 0x00000080;
baseParams.ExStyle |= ( int )( WS_EX_NOACTIVATE | WS_EX_TOOLWINDOW );
return baseParams;
}
}

Stolen from PInvoke.net's ShowWindow method:
private const int SW_SHOWNOACTIVATE = 4;
private const int HWND_TOPMOST = -1;
private const uint SWP_NOACTIVATE = 0x0010;
[DllImport("user32.dll", EntryPoint = "SetWindowPos")]
static extern bool SetWindowPos(
int hWnd, // Window handle
int hWndInsertAfter, // Placement-order handle
int X, // Horizontal position
int Y, // Vertical position
int cx, // Width
int cy, // Height
uint uFlags); // Window positioning flags
[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
static void ShowInactiveTopmost(Form frm)
{
ShowWindow(frm.Handle, SW_SHOWNOACTIVATE);
SetWindowPos(frm.Handle.ToInt32(), HWND_TOPMOST,
frm.Left, frm.Top, frm.Width, frm.Height,
SWP_NOACTIVATE);
}
(Alex Lyman answered this, I'm just expanding it by directly pasting the code. Someone with edit rights can copy it over there and delete this for all I care ;) )

This is what worked for me. It provides TopMost but without focus-stealing.
protected override bool ShowWithoutActivation
{
get { return true; }
}
private const int WS_EX_TOPMOST = 0x00000008;
protected override CreateParams CreateParams
{
get
{
CreateParams createParams = base.CreateParams;
createParams.ExStyle |= WS_EX_TOPMOST;
return createParams;
}
}
Remember to omit setting TopMost in Visual Studio designer, or elsewhere.
This is stolen, err, borrowed, from here (click on Workarounds):
https://connect.microsoft.com/VisualStudio/feedback/details/401311/showwithoutactivation-is-not-supported-with-topmost

If you're willing to use Win32 P/Invoke, then you can use the ShowWindow method (the first code sample does exactly what you want).

Doing this seems like a hack, but it seems to work:
this.TopMost = true; // as a result the form gets thrown to the front
this.TopMost = false; // but we don't actually want our form to always be on top
Edit: Note, this merely raises an already created form without stealing focus.

The sample code from pinvoke.net in Alex Lyman/TheSoftwareJedi's answers will make the window a "topmost" window, meaning that you can't put it behind normal windows after it's popped up. Given Matias's description of what he wants to use this for, that could be what he wants. But if you want the user to be able to put your window behind other windows after you've popped it up, just use HWND_TOP (0) instead of HWND_TOPMOST (-1) in the sample.

In WPF you can solve it like this:
In the window put these attributes:
<Window
x:Class="myApplication.winNotification"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Notification Popup" Width="300" SizeToContent="Height"
WindowStyle="None" AllowsTransparency="True" Background="Transparent" ShowInTaskbar="False" Topmost="True" Focusable="False" ShowActivated="False" >
</Window>
The last one attribute is the one you need ShowActivated="False".

I have something similar, and I simply show the notification form and then do
this.Focus();
to bring the focus back on the main form.

Create and start the notification Form in a separate thread and reset the focus back to your main form after the Form opens. Have the notification Form provide an OnFormOpened event that is fired from the Form.Shown event. Something like this:
private void StartNotfication()
{
Thread th = new Thread(new ThreadStart(delegate
{
NotificationForm frm = new NotificationForm();
frm.OnFormOpen += NotificationOpened;
frm.ShowDialog();
}));
th.Name = "NotificationForm";
th.Start();
}
private void NotificationOpened()
{
this.Focus(); // Put focus back on the original calling Form
}
You can also keep a handle to your NotifcationForm object around so that it can be programmatically closed by the main Form (frm.Close()).
Some details are missing, but hopefully this will get you going in the right direction.

This works well.
See: OpenIcon - MSDN and SetForegroundWindow - MSDN
using System.Runtime.InteropServices;
[DllImport("user32.dll")]
static extern bool OpenIcon(IntPtr hWnd);
[DllImport("user32.dll")]
static extern bool SetForegroundWindow(IntPtr hWnd);
public static void ActivateInstance()
{
IntPtr hWnd = IntPtr hWnd = Process.GetCurrentProcess().MainWindowHandle;
// Restore the program.
bool result = OpenIcon(hWnd);
// Activate the application.
result = SetForegroundWindow(hWnd);
// End the current instance of the application.
//System.Environment.Exit(0);
}

You might want to consider what kind of notification you would like to display.
If it's absolutely critical to let the user know about some event, using Messagebox.Show would be the recommended way, due to its nature to block any other events to the main window, until the user confirms it. Be aware of pop-up blindness, though.
If it's less than critical, you might want to use an alternative way to display notifications, such as a toolbar on the bottom of the window. You wrote, that you display notifications on the bottom-right of the screen - the standard way to do this would be using a balloon tip with the combination of a system tray icon.

You can handle it by logic alone too, although I have to admit that the suggestions above where you end up with a BringToFront method without actually stealing focus is the most elegant one.
Anyhow, I ran into this and solved it by using a DateTime property to not allow further BringToFront calls if calls were made already recently.
Assume a core class, 'Core', which handles for example three forms, 'Form1, 2, and 3'. Each form needs a DateTime property and an Activate event that call Core to bring windows to front:
internal static DateTime LastBringToFrontTime { get; set; }
private void Form1_Activated(object sender, EventArgs e)
{
var eventTime = DateTime.Now;
if ((eventTime - LastBringToFrontTime).TotalMilliseconds > 500)
Core.BringAllToFront(this);
LastBringToFrontTime = eventTime;
}
And then create the work in the Core Class:
internal static void BringAllToFront(Form inForm)
{
Form1.BringToFront();
Form2.BringToFront();
Form3.BringToFront();
inForm.Focus();
}
On a side note, if you want to restore a minimized window to its original state (not maximized), use:
inForm.WindowState = FormWindowState.Normal;
Again, I know this is just a patch solution in the lack of a BringToFrontWithoutFocus. It is meant as a suggestion if you want to avoid the DLL file.

I don't know if this is considered as necro-posting, but this is what I did since I couln't get it working with user32's "ShowWindow" and "SetWindowPos" methods. And no, overriding "ShowWithoutActivation" doesn't work in this case since the new window should be always-on-top.
Anyway, I created a helper method that takes a form as parameter; when called, it shows the form, brings it to the front and makes it TopMost without stealing the focus of the current window (apparently it does, but the user won't notice).
[DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
static extern IntPtr SetForegroundWindow(IntPtr hWnd);
public static void ShowTopmostNoFocus(Form f)
{
IntPtr activeWin = GetForegroundWindow();
f.Show();
f.BringToFront();
f.TopMost = true;
if (activeWin.ToInt32() > 0)
{
SetForegroundWindow(activeWin);
}
}

I know it may sound stupid, but this worked:
this.TopMost = true;
this.TopMost = false;
this.TopMost = true;
this.SendToBack();

I needed to do this with my window TopMost. I implemented the PInvoke method above but found that my Load event wasn't getting called like Talha above. I finally succeeded. Maybe this will help someone. Here is my solution:
form.Visible = false;
form.TopMost = false;
ShowWindow(form.Handle, ShowNoActivate);
SetWindowPos(form.Handle, HWND_TOPMOST,
form.Left, form.Top, form.Width, form.Height,
NoActivate);
form.Visible = true; //So that Load event happens

You don't need to make it anywhere near as complicated.
a = new Assign_Stock();
a.MdiParent = this.ParentForm;
a.Visible = false; //hide for a bit.
a.Show(); //show the form. Invisible form now at the top.
this.Focus(); //focus on this form. make old form come to the top.
a.Visible = true; //make other form visible now. Behind the main form.

Github Sample
Form.ShowWithoutActivation Property
Add this in your child form class
protected override bool ShowWithoutActivation
{
get { return true; }
}
Working Code
Form2
public partial class Form2 : Form
{
Form3 c;
public Form2()
{
InitializeComponent();
c = new Form3();
}
private void textchanged(object sender, EventArgs e)
{
c.ResetText(textBox1.Text.ToString());
c.Location = new Point(this.Location.X+150, this.Location.Y);
c .Show();
//removethis
//if mdiparent 2 add this.focus() after show form
c.MdiParent = this.MdiParent;
c.ResetText(textBox1.Text.ToString());
c.Location = new Point(this.Location.X+150, this.Location.Y);
c .Show();
this.Focus();
////-----------------
}
}
Form3
public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();
//ShowWithoutActivation = false;
}
protected override bool ShowWithoutActivation
{
get { return true; }
}
internal void ResetText(string toString)
{
label2.Text = toString;
}
}

When you create a new form using
Form f = new Form();
f.ShowDialog();
it steals focus because your code can't continue executing on the main form until this form is closed.
The exception is by using threading to create a new form then Form.Show(). Make sure the thread is globally visible though, because if you declare it within a function, as soon as your function exits, your thread will end and the form will disappear.

Figured it out: window.WindowState = WindowState.Minimized;.

Start menu will cover the Window when not open in Visual Studio

I have create a Window use WPF, I want to my Window always display on the top, So I just create a thread for it:
System.Threading.Tasks.Task.Factory.StartNew(() =>
{
for (;;)
{
System.Threading.Thread.Sleep(3000);
this.Dispatcher.BeginInvoke(new Action(() =>
{
this.Activate();
this.Topmost = true;
}));
}
});
}
This will make sure my window go to front in every 3 seconds.
And when I open it under Visual Studio 2015, all fine, even when I open the Start Menu, it will close start menu and bring the window on top.But when I'm not use Visual studio open the application(just double click open the application), when I open start menu, the Window just flickering, not display on the top. What I miss? and how do I let it work as like open the application under Visual Studio 2015(I'm tested on Win10)?

EDIT: I somehow missed the point covered in the title. The point I make later of "Do not do it" still holds true though. It could cause problems for users of your application.
If you really need to though, this answer may be the one you are looking for. It discusses how to keep a window in front of everything. It is still a work around (just like most answers to your question).
Old Answer
I understand your problem as: you want your window to stay on top of all other windows. Similar functionality can be found in Ubuntu and The Google Play Music desktop application for Window's (see below).
To accomplish this, all you need to do is add Topmost="True" to your Window as demonstrated below (look at the last property).
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Topmost="True">
</Window>
Unless your actual problem "is what happens when two windows have that property set?" Then I would suggest reading this article (the same article that was referenced in the comments). It states the following:
"How do I create a window that is never covered by any other windows, not even other topmost windows?"
Imagine if this were possible and imagine if two programs did this.
Program A creates a window that is "super-topmost" and so does Program
B. Now the user drags the two windows so that they overlap. What
happens? You've created yourself a logical impossibility. One of those
two windows must be above the other, contradicting the imaginary
"super-topmost" feature.
If that functionality is really what you are after, I would suggest: do not do it. All other solutions are a workaround and could cause problems for consumers of your application.

I would have used interop to do this.
public class Interop
{
[DllImport("user32.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd);
[DllImport("user32.dll")]
public static extern bool ShowWindow(IntPtr hwind, int cmd);
[DllImport("user32.dll")]
public static extern IntPtr GetForegroundWindow();
public static IntPtr GetWindowHandle(Window window)
{
return new WindowInteropHelper(window).Handle;
}
}
then use a timer:
private void Tick(object state)
{
this.Dispatcher.Invoke(() =>
{
IntPtr window = Interop.GetWindowHandle(this);
IntPtr focused = Interop.GetForegroundWindow();
if (window != focused)
{
Interop.SetForegroundWindow(window);
// Command 5 for show
Interop.ShowWindow(window, 5);
}
});
}
Code from
And for the part of your problem regarding the startmenu, just add a group policy.
Or you can make a interop to ´FindWindowEx´ to find the startbutton and disable it.

I agree with Jonas's answer but would modify it to use an event instead of a timer.
/// Get the topmost window handle
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern IntPtr GetForegroundWindow();
/// Trigger event when topmost window changed
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, TopmostWindowChangedDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);
/// Set the topmost window
[DllImport("user32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
/// Show a window
[DllImport("user32.dll")]
private static extern bool ShowWindow(IntPtr hwind, int cmd);
// Constant variables for topmost window changed event
private const uint WINEVENT_OUTOFCONTEXT = 0;
private const uint EVENT_SYSTEM_FOREGROUND = 3;
/// Keep track of the last topmost window with a name
private static IntPtr topWinHandle { get; set; }
/// Implementation of topmost window changed delegate
private TopmostWindowChangedDelegate TopmostWindowChanged { get; set; }
Then set up the handlers in one of your startup methods
// Set topmost window changed event handler
TopmostWindowChanged = new TopmostWindowChangedDelegate(WinEventProc);
// Set event hook for topmost window changed
IntPtr hook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, TopmostWindowChanged, 0, 0, WINEVENT_OUTOFCONTEXT);
And then move your window to topmost when the other topmost changes
/// Make sure this window stays on top
public void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
// Get current window name from handle
IntPtr handle = GetForegroundWindow();
if(handle != YOUR_WINDOW'S_HANDLE)
{
// Move your window back to the top
SetForegroundWindow(YOUR_WINDOW'S_HANDLE);
ShowWindow(YOUR_WINDOW'S_HANDLE, 5);
}
}

When closing Console Window its close the all application

I'm working with windows form and i have a main form and when I click on some button he open a console window that do some work and when its done I want to close the console without closing the all application (main form). I try to close the console with Environment.Exit(1) or the function Destroy() that belongs to the Destroy() and Create() the console window. the Environment.Exit(1) and Destroy() both close the console but close the form too.
I wonder if there is a way to close only the console without closing the whole application
EDIT
private void btSync_Click(object sender, EventArgs e)
{
Create();
ServerSync sycs=new ServerSync();
Thread sync = new Thread(new ThreadStart(sycs.run));
sync.Start();
}
The Create() open a Console window that run a Socket() Thread.
Problem Solved
When im start the thread i add to the end of code a ThreadName.Abort and outside the thread i check if ThreadName.IsAlived==false and inside the if i Hide() the console and then Destroy() And Its Works!
the Hide() method from AppDeveloper answer.
Thanks for your help!

Instead of using Environment.Exit() hide the Console Window
using System.Runtime.InteropServices;
[DllImport("kernel32.dll")]
static extern IntPtr GetConsoleWindow();
[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
const int SW_HIDE = 0x0;
const int SW_SHOW = 0x5;
public static void HideConsoleWindow()
{
var handle = GetConsoleWindow();
ShowWindow(handle, SW_HIDE);
}

Maybe there is a console.hide() option? could try that out.

How to prevent my C# winforms application from stealing focus when I set the visible properly to true?

I've got a C# winforms application that runs in the background, listening for hotkeys to be pressed. When a hotkey is pressed, my form makes a brief appearance. The form is always running, but set to hidden until I receive a hotkey event, at which time I set the visible property to true. The code looks like this:
void hook_volumeDown(object sender, KeyPressedEventArgs e)
{
this.Visible = true;
}
It should be noted that the topmost property of this form is set to true.
The really odd part is, after my C# app has stolen focus from another application, it will never do it again. For example: I launch my app, then launch some fullscreep app like Team Fortress 2. Then I press my hotkey. Team Fortress 2 minimizes, and I see my form. Then, however, I can restore TF2, and press my hotkey again all I want (with the desired effect), and TF2 will remain focused.
At any rate, I'm looking for a way to fix this. I've found a lot of questions here covering similar problems, but all of them are related to creating/launching a new form, not making an existing one visible (unless I missed something). I could rework the application to create a new form every time I need one, but that would entail creating yet another form to be invisible all the time just to wait for hotkey events, so I'd rather leave it as it is.
Any ideas?

I think you problem is related to the fact that Visible = true behaves differently between the first and subsequent calls. The first time visible is called and the window handle has not been created, the Window is created by calling CreateWindowEx which has some style parameters which controls how the window should behave. I think you need to make sure that the window is created with the style WS_EX_NOACTIVATE, which you can do by overriding CreateParams.
Other things to try out:
1) The ShowWindow function (used by Visible = true) ignores the focus parameter the first time it is called (http://msdn.microsoft.com/en-us/library/ms633548%28VS.85%29.aspx) if the program provides a STARTUPINFO structure. Dig into reflector and find out if the Form class provides a STARTUPINFO structure and if so, how to manipulate it.
2) The Form has a ShowWithoutActivation property than can be overriden and set to true, have you overriden this?
Sorry for the "no exact answer", but I hope this at least gives you some starting points for further investigation. Good luck.

Seeing KeyPressedEventArgs being used in your function looks really strange. Hot keys can be implemented by P/Invoking the RegisterHotKey() API function. It sends a message to your window when the hot key is pressed. Here's an example of a form that's invisible at start up, springs alive when you press the hot key. Ctrl+Alt+U in this case:
using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WindowsFormsApplication1 {
public partial class Form1 : Form {
private const int MYKEYID = 0; // In case you want to register more than one...
public Form1() {
InitializeComponent();
this.FormClosing += (s, args) => UnregisterHotKey(this.Handle, MYKEYID);
}
protected override void SetVisibleCore(bool value) {
if (value && !this.IsHandleCreated) {
this.CreateHandle();
RegisterHotKey(this.Handle, MYKEYID, MOD_CONTROL + MOD_SHIFT, Keys.U);
value = false;
}
base.SetVisibleCore(value);
}
protected override void WndProc(ref Message m) {
if (m.Msg == WM_HOTKEY && m.WParam.ToInt32() == MYKEYID) {
this.Visible = true;
if (this.WindowState == FormWindowState.Minimized)
this.WindowState = FormWindowState.Normal;
SetForegroundWindow(this.Handle);
}
base.WndProc(ref m);
}
// P/Invoke declarations
private const int WM_HOTKEY = 0x312;
private const int MOD_ALT = 1;
private const int MOD_CONTROL = 2;
private const int MOD_SHIFT = 4;
[DllImport("user32.dll")]
private static extern int RegisterHotKey(IntPtr hWnd, int id, int modifier, Keys vk);
[DllImport("user32.dll")]
private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
[DllImport("user32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
}
}
Note that the SetForegroundWindow() function is the rub, possibly also the source of the problem you describe in your question. Windows doesn't permit an app to shove a window in the user's face when the user is actively using another window. At least several seconds of inactivity must expire before it will allow the window to steal the focus. With the given code, that is easy enough to see, the taskbar button of your form will be blinking. Avoid setting the ShowInTaskbar property to false. It isn't necessary to do so with this code, the taskbar button won't show up until the hot key is pressed.

Bring a window to the front in WPF

How can I bring my WPF application to the front of the desktop? So far I've tried:
SwitchToThisWindow(new WindowInteropHelper(Application.Current.MainWindow).Handle, true);
SetWindowPos(new WindowInteropHelper(Application.Current.MainWindow).Handle, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
SetForegroundWindow(new WindowInteropHelper(Application.Current.MainWindow).Handle);
None of which are doing the job (Marshal.GetLastWin32Error() is saying these operations completed successfully, and the P/Invoke attributes for each definition do have SetLastError=true).
If I create a new blank WPF application, and call SwitchToThisWindow with a timer, it works exactly as expected, so I'm not sure why it's not working in my original case.
Edit: I'm doing this in conjunction with a global hotkey.

myWindow.Activate();
Attempts to bring the window to the foreground and activates it.
That should do the trick, unless I misunderstood and you want Always on Top behavior. In that case you want:
myWindow.TopMost = true;

I have found a solution that brings the window to the top, but it behaves as a normal window:
if (!Window.IsVisible)
{
Window.Show();
}
if (Window.WindowState == WindowState.Minimized)
{
Window.WindowState = WindowState.Normal;
}
Window.Activate();
Window.Topmost = true; // important
Window.Topmost = false; // important
Window.Focus(); // important

In case you need the window to be in front the first time it loads then you should use the following:
private void Window_ContentRendered(object sender, EventArgs e)
{
this.Topmost = false;
}
private void Window_Initialized(object sender, EventArgs e)
{
this.Topmost = true;
}
Or by overriding the methods:
protected override void OnContentRendered(EventArgs e)
{
base.OnContentRendered(e);
Topmost = false;
}
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
Topmost = true;
}

I know this question is rather old, but I've just come across this precise scenario and wanted to share the solution I've implemented.
As mentioned in comments on this page, several of the solutions proposed do not work on XP, which I need to support in my scenario. While I agree with the sentiment by #Matthew Xavier that generally this is a bad UX practice, there are times where it's entirely a plausable UX.
The solution to bringing a WPF window to the top was actually provided to me by the same code I'm using to provide the global hotkey. A blog article by Joseph Cooney contains a link to his code samples that contains the original code.
I've cleaned up and modified the code a little, and implemented it as an extension method to System.Windows.Window. I've tested this on XP 32 bit and Win7 64 bit, both of which work correctly.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Interop;
using System.Runtime.InteropServices;
namespace System.Windows
{
public static class SystemWindows
{
#region Constants
const UInt32 SWP_NOSIZE = 0x0001;
const UInt32 SWP_NOMOVE = 0x0002;
const UInt32 SWP_SHOWWINDOW = 0x0040;
#endregion
/// <summary>
/// Activate a window from anywhere by attaching to the foreground window
/// </summary>
public static void GlobalActivate(this Window w)
{
//Get the process ID for this window's thread
var interopHelper = new WindowInteropHelper(w);
var thisWindowThreadId = GetWindowThreadProcessId(interopHelper.Handle, IntPtr.Zero);
//Get the process ID for the foreground window's thread
var currentForegroundWindow = GetForegroundWindow();
var currentForegroundWindowThreadId = GetWindowThreadProcessId(currentForegroundWindow, IntPtr.Zero);
//Attach this window's thread to the current window's thread
AttachThreadInput(currentForegroundWindowThreadId, thisWindowThreadId, true);
//Set the window position
SetWindowPos(interopHelper.Handle, new IntPtr(0), 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE | SWP_SHOWWINDOW);
//Detach this window's thread from the current window's thread
AttachThreadInput(currentForegroundWindowThreadId, thisWindowThreadId, false);
//Show and activate the window
if (w.WindowState == WindowState.Minimized) w.WindowState = WindowState.Normal;
w.Show();
w.Activate();
}
#region Imports
[DllImport("user32.dll")]
private static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
private static extern uint GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);
[DllImport("user32.dll")]
private static extern bool AttachThreadInput(uint idAttach, uint idAttachTo, bool fAttach);
[DllImport("user32.dll")]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);
#endregion
}
}
I hope this code helps others who encounter this problem.

To make this a quick copy-paste one -
Use this class' DoOnProcess method to move process' main window to foreground (but not to steal focus from other windows)
public class MoveToForeground
{
[DllImportAttribute("User32.dll")]
private static extern int FindWindow(String ClassName, String WindowName);
const int SWP_NOMOVE = 0x0002;
const int SWP_NOSIZE = 0x0001;
const int SWP_SHOWWINDOW = 0x0040;
const int SWP_NOACTIVATE = 0x0010;
[DllImport("user32.dll", EntryPoint = "SetWindowPos")]
public static extern IntPtr SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int Y, int cx, int cy, int wFlags);
public static void DoOnProcess(string processName)
{
var allProcs = Process.GetProcessesByName(processName);
if (allProcs.Length > 0)
{
Process proc = allProcs[0];
int hWnd = FindWindow(null, proc.MainWindowTitle.ToString());
// Change behavior by settings the wFlags params. See http://msdn.microsoft.com/en-us/library/ms633545(VS.85).aspx
SetWindowPos(new IntPtr(hWnd), 0, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_SHOWWINDOW | SWP_NOACTIVATE);
}
}
}
HTH

Why some of the answers on this page are wrong!
Any answer that uses window.Focus() is wrong.
Why? If a notification message pops up, window.Focus() will grab the focus away from whatever the user is typing at the time. This is insanely frustrating for end users, especially if the popups occur quite frequently.
Any answer that uses window.Activate() is wrong.
Why? It will make any parent windows visible as well.
Any answer that omits window.ShowActivated = false is wrong.
Why? It will grab the focus away from another window when the message pops up which is very annoying!
Any answer that does not use Visibility.Visible to hide/show the window is wrong.
Why? If we are using Citrix, if the window is not collapsed when it is closed, it will leave a weird black rectangular hold on the screen. Thus, we cannot use window.Show() and window.Hide().
Essentially:
The window should not grab the focus away from any other window when it activates;
The window should not activate its parent when it is shown;
The window should be compatible with Citrix.
MVVM Solution
This code is 100% compatible with Citrix (no blank areas of the screen). It is tested with both normal WPF and DevExpress.
This answer is intended for any use case where we want a small notification window that is always in front of other windows (if the user selects this in the preferences).
If this answer seems more complex than the others, it's because it is robust, enterprise level code. Some of the other answers on this page are simple, but do not actually work.
XAML - Attached Property
Add this attached property to any UserControl within the window. The attached property will:
Wait until the Loaded event is fired (otherwise it cannot look up the visual tree to find the parent window).
Add an event handler that ensures that the window is visible or not.
At any point, you can set the window to be in front or not, by flipping the value of the attached property.
<UserControl x:Class="..."
...
attachedProperties:EnsureWindowInForeground.EnsureWindowInForeground=
"{Binding EnsureWindowInForeground, Mode=OneWay}">
C# - Helper Method
public static class HideAndShowWindowHelper
{
/// <summary>
/// Intent: Ensure that small notification window is on top of other windows.
/// </summary>
/// <param name="window"></param>
public static void ShiftWindowIntoForeground(Window window)
{
try
{
// Prevent the window from grabbing focus away from other windows the first time is created.
window.ShowActivated = false;
// Do not use .Show() and .Hide() - not compatible with Citrix!
if (window.Visibility != Visibility.Visible)
{
window.Visibility = Visibility.Visible;
}
// We can't allow the window to be maximized, as there is no de-maximize button!
if (window.WindowState == WindowState.Maximized)
{
window.WindowState = WindowState.Normal;
}
window.Topmost = true;
}
catch (Exception)
{
// Gulp. Avoids "Cannot set visibility while window is closing".
}
}
/// <summary>
/// Intent: Ensure that small notification window can be hidden by other windows.
/// </summary>
/// <param name="window"></param>
public static void ShiftWindowIntoBackground(Window window)
{
try
{
// Prevent the window from grabbing focus away from other windows the first time is created.
window.ShowActivated = false;
// Do not use .Show() and .Hide() - not compatible with Citrix!
if (window.Visibility != Visibility.Collapsed)
{
window.Visibility = Visibility.Collapsed;
}
// We can't allow the window to be maximized, as there is no de-maximize button!
if (window.WindowState == WindowState.Maximized)
{
window.WindowState = WindowState.Normal;
}
window.Topmost = false;
}
catch (Exception)
{
// Gulp. Avoids "Cannot set visibility while window is closing".
}
}
}
Usage
In order to use this, you need to create the window in your ViewModel:
private ToastView _toastViewWindow;
private void ShowWindow()
{
if (_toastViewWindow == null)
{
_toastViewWindow = new ToastView();
_dialogService.Show<ToastView>(this, this, _toastViewWindow, true);
}
ShiftWindowOntoScreenHelper.ShiftWindowOntoScreen(_toastViewWindow);
HideAndShowWindowHelper.ShiftWindowIntoForeground(_toastViewWindow);
}
private void HideWindow()
{
if (_toastViewWindow != null)
{
HideAndShowWindowHelper.ShiftWindowIntoBackground(_toastViewWindow);
}
}
Additional links
For tips on how ensure that a notification window always shifts back onto the visible screen, see my answer: In WPF, how to shift a window onto the screen if it is off the screen?.

If the user is interacting with another application, it may not be possible to bring yours to the front. As a general rule, a process can only expect to set the foreground window if that process is already the foreground process. (Microsoft documents the restrictions in the SetForegroundWindow() MSDN entry.) This is because:
The user "owns" the foreground. For example, it would be extremely annoying if another program stole the foreground while the user is typing, at the very least interrupting her workflow, and possibly causing unintended consequences as her keystrokes meant for one application are misinterpreted by the offender until she notices the change.
Imagine that each of two programs checks to see if its window is the foreground and attempts to set it to the foreground if it is not. As soon as the second program is running, the computer is rendered useless as the foreground bounces between the two at every task switch.

I know that this is late answer, maybe helpful for researchers
if (!WindowName.IsVisible)
{
WindowName.Show();
WindowName.Activate();
}

I have had a similar problem with a WPF application that gets invoked from an Access application via the Shell object.
My solution is below - works in XP and Win7 x64 with app compiled to x86 target.
I'd much rather do this than simulate an alt-tab.
void Window_Loaded(object sender, RoutedEventArgs e)
{
// make sure the window is normal or maximised
// this was the core of the problem for me;
// even though the default was "Normal", starting it via shell minimised it
this.WindowState = WindowState.Normal;
// only required for some scenarios
this.Activate();
}

Well, since this is such a hot topic... here is what works for me. I got errors if I didn't do it this way because Activate() will error out on you if you cannot see the window.
Xaml:
<Window ....
Topmost="True"
....
ContentRendered="mainWindow_ContentRendered"> .... </Window>
Codebehind:
private void mainWindow_ContentRendered(object sender, EventArgs e)
{
this.Topmost = false;
this.Activate();
_UsernameTextBox.Focus();
}
This was the only way for me to get the window to show on top. Then activate it so you can type in the box without having to set focus with the mouse. control.Focus() wont work unless the window is Active();

Well I figured out a work around. I'm making the call from a keyboard hook used to implement a hotkey. The call works as expected if I put it into a BackgroundWorker with a pause. It's a kludge, but I have no idea why it wasn't working originally.
void hotkey_execute()
{
IntPtr handle = new WindowInteropHelper(Application.Current.MainWindow).Handle;
BackgroundWorker bg = new BackgroundWorker();
bg.DoWork += new DoWorkEventHandler(delegate
{
Thread.Sleep(10);
SwitchToThisWindow(handle, true);
});
bg.RunWorkerAsync();
}

To show ANY currently opened window import those DLL:
public partial class Form1 : Form
{
[DllImportAttribute("User32.dll")]
private static extern int FindWindow(String ClassName, String WindowName);
[DllImportAttribute("User32.dll")]
private static extern int SetForegroundWindow(int hWnd);
and in program We search for app with specified title (write title without first letter (index > 0))
foreach (Process proc in Process.GetProcesses())
{
tx = proc.MainWindowTitle.ToString();
if (tx.IndexOf("Title of Your app WITHOUT FIRST LETTER") > 0)
{
tx = proc.MainWindowTitle;
hWnd = proc.Handle.ToInt32(); break;
}
}
hWnd = FindWindow(null, tx);
if (hWnd > 0)
{
SetForegroundWindow(hWnd);
}

These codes will work fine all times.
At first set the activated event handler in XAML:
Activated="Window_Activated"
Add below line to your Main Window constructor block:
public MainWindow()
{
InitializeComponent();
this.LocationChanged += (sender, e) => this.Window_Activated(sender, e);
}
And inside the activated event handler copy this codes:
private void Window_Activated(object sender, EventArgs e)
{
if (Application.Current.Windows.Count > 1)
{
foreach (Window win in Application.Current.Windows)
try
{
if (!win.Equals(this))
{
if (!win.IsVisible)
{
win.ShowDialog();
}
if (win.WindowState == WindowState.Minimized)
{
win.WindowState = WindowState.Normal;
}
win.Activate();
win.Topmost = true;
win.Topmost = false;
win.Focus();
}
}
catch { }
}
else
this.Focus();
}
These steps will works fine and will bring to front all other windows into their parents window.

Just wanted to add another solution to this question. This implementation works for my scenario, where CaliBurn is responsible for displaying the main Window.
protected override void OnStartup(object sender, StartupEventArgs e)
{
DisplayRootViewFor<IMainWindowViewModel>();
Application.MainWindow.Topmost = true;
Application.MainWindow.Activate();
Application.MainWindow.Activated += OnMainWindowActivated;
}
private static void OnMainWindowActivated(object sender, EventArgs e)
{
var window = sender as Window;
if (window != null)
{
window.Activated -= OnMainWindowActivated;
window.Topmost = false;
window.Focus();
}
}

The problem could be that the thread calling your code from the hook hasn't been initialized by the runtime so calling runtime methods don't work.
Perhaps you could try doing an Invoke to marshal your code on to the UI thread to call your code that brings the window to the foreground.

If you are trying to hide the window, for example you minimize the window, I have found that using
this.Hide();
will hide it correctly, then simply using
this.Show();
will then show the window as the top most item once again.

Remember not to put the code that shows that window inside a PreviewMouseDoubleClick handler as the active window will switch back to the window who handled the event.
Just put it in the MouseDoubleClick event handler or stop bubbling by setting e.Handled to True.
In my case i was handling the PreviewMouseDoubleClick on a Listview and was not setting the e.Handled = true then it raised the MouseDoubleClick event witch sat focus back to the original window.

This is a combination of a few suggestions above that works well and is simple. It only comes to front when those events fire, so any window that pops up after the event will stay on top of course.
public partial class MainWindow : Window
{
protected override void OnContentRendered(EventArgs e)
{
base.OnContentRendered(e);
Topmost = true;
Topmost = false;
}
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
Topmost = true;
Topmost = false;
}
....
}

I wanted to create a launcher with the keyboard hook and had the same problem.
After much trial and error, this solved the problem.
void Active()
{
MainWindow0.Show();
MainWindow0.Focus();
MainWindow0.Activate();
MainWindow0.WindowState = WindowState.Normal;
}
void Deactive()
{
MainWindow0.Hide();
MainWindow0.WindowState = WindowState.Minimized;
}

I built an extension method to make for easy reuse.
using System.Windows.Forms;
namespace YourNamespace{
public static class WindowsFormExtensions {
public static void PutOnTop(this Form form) {
form.Show();
form.Activate();
}// END PutOnTop()
}// END class
}// END namespace
Call in the Form Constructor
namespace YourNamespace{
public partial class FormName : Form {
public FormName(){
this.PutOnTop();
InitalizeComponents();
}// END Constructor
} // END Form
}// END namespace